Investigating the photo-excited electronic state of a spin-valley coupled semiconductor

Research Project

Project/Area Number	16K13815
Research Category	Grant-in-Aid for Challenging Exploratory Research
Allocation Type	Multi-year Fund
Research Field	Condensed matter physics I
Research Institution	The University of Tokyo
Principal Investigator	Ishizaka Kyoko 東京大学, 大学院工学系研究科(工学部), 准教授 (20376651)
Project Period (FY)	2016-04-01 – 2017-03-31
Project Status	Completed (Fiscal Year 2016)
Budget Amount *help	¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000) Fiscal Year 2016: ¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000)
Keywords	光電子分光 / 超高速現象 / 半導体 / 物性実験
Outline of Final Research Achievements	We investigated the ultrafast dynamics of the electronic structure in a non-centrosymmetric spin-valley coupled semiconductor 3R-MoS2, by utilizing the femto-second time-resolved photoemission spectroscopy. In the time region of several picoseconds after the photoexcitation, we found the electron transferring from the valence band to the conduction band, with the simultaneous decrease of the band gap. The systematic time delay dependence indicates that the suppression of the band gap is closely related to the electron-hole excited state.